For the first time, a lateral or blindside hit on an opponent in which the head is targeted or is the main area of impact will not only be subject to supplemental discipline, but a major penalty and ejection from the game.

Players have had only last season's playoffs and one exhibition season to alter their play and keep their shoulders away from the head when they hit an unsuspecting opponent.

"We've seen a couple of blindside hits, shoulder to shoulder, shoulder to chest, that are still legal," league disciplinarian Colin Campbell said. "I can't tell you that I've seen exactly a player who's tried to avoid it. Hopefully they are avoiding it."

Savard is still bothered by the effects of a concussion he sustained March 7 when he was hit from behind by Pittsburgh's Cooke. Savard missed the rest of the regular season and didn't return to the Bruins' lineup until the first game of Boston's second-round playoff series against Philadelphia.

Booth, a Florida Panthers forward, missed 45 games because of a concussion he received after Richards' blindside hit in Philadelphia on Oct. 24.

"As the players got bigger, the hits became more frequent," Campbell said. "We took a look at this as our concussion study was taking place. The (general managers) said, 'Enough. We have to do something about these concussions.' Certainly that got us going. We were going to do something about it."

The board of governors, general managers and the league's competition committee unanimously agreed that these specific hits no longer had a place in the game, but they stopped short of eliminating all head contact.

"The hitter really has to be cognizant of where he's coming from and where the contact is going to be made with the player," said Terry Gregson, the NHL's director of officiating. "There's still going to be contact with the head. If it's coming from the blindside, my guys are to penalize that player.

"We can't lose sight of the fact there's going to be elbowing majors to the head and things like that. Those don't go out the window. I don't want guys to morph to this rule every time there's contact with the head."

Before this season, violators only had to worry about suspensions. Now these infractions also will impact the games in which the hits occur.

"Our managers felt at this point in time we had to shift the responsibility from the player getting hit to the player delivering the hit," Campbell said. "One of the aspects that really drove the managers to make this decision was the fact that 50 percent of our concussions in the NHL were delivered from the side.

"Our managers felt by getting rid of this particular hit ... it would essentially reduce concussions. Hockey is a hitting game. Like saves, goals, other things in the game, it's part of the entertainment aspect and part of the game of hockey. Our managers were sensitive about removing hitting altogether."

The style and long-standing tradition of clean contact in hockey is important to players, too, and they want that aspect of the game to be preserved.

But they understand that their careers and long-term health are on the line while playing a sport that is fast and violent by nature.

"You want to keep the history of the game and you want to keep the game the same. That's fine," Montreal Canadiens forward Mike Cammalleri said. "I am a romantic when it comes to sports, especially hockey. But at the same time let's not be ignorant. The guys are bigger, stronger, faster. The game is evolving as far as the athletes, the equipment and on and on and on.

"Golf courses played at 6,500 yards and now they're playing at 7,500 yards. There's a reason for that. It's the same thing in hockey. There are certain subtle changes that need to take place to keep our game as exciting as possible."

He's only 17 but he can see the ice so well and he moves the puck and goes to the open ice all the time, so I just think he's a player that is ready to play in the NHL. I'm really looking forward to coaching someone like this.

— U.S. National Junior Team coach Ron Wilson on Auston Matthews, the projected No. 1 pick of the 2016 NHL Draft